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I have been driving all day, not non stop but running errands and stuff. While on my way to Colorado Springs I stop at a stop light and my car turns off. The battery light and oil light come on. I start it back up and it studders a little bit, I get off the main road and pull over. When I stop it shuts off again, I open the hood and wait. I called my mechanic and she advised me to pull up the back seat and hit where the fuel pump cord is behind the passenger seat and try turning it on while doing so. So I did so and my gf started the car and it worked but I could only drive about 3 blocks before it did it again. The 3rd time I noticed the RPM Gage was stuck at 2. I wait about 30 mins and then drive 2 blocks up the street to get out of the sun while waiting for the tow truck. I was able to start the car 4 or 5 times while waiting for the tow truck but the car did not shut off any of those times. I did noticed the first 2 times that it wanted to shut off because it was acting as if it was gasping for something. After waiting 3 hours the tow arrived and once I got home I was able to drive the car into my garage and park it, while doing this none of the previous symptoms occured. What the hell is going on ?!?!? My mechanic thinks its the fuel pump but I have been reading about the possibility of vapor lock. If it is vapor lock will replacing the fuel pump fix it and if not how do I stop it from vapor locking? Are there any other possibilities it could be and has anyone else had any issues like this?? I bought this car in April and love it but to be completely honest I am absolutely mortified about this situation, any help would be great.

I'm having this same exact issue. Car has 101,xxx miles on it...throwing O2 sensor codes...but have had this problem since 80k and still do not know what it is...have you taken your car to the dealer yet?

I'm having this same exact issue. Car has 101,xxx miles on it...throwing O2 sensor codes...but have had this problem since 80k and still do not know what it is...have you taken your car to the dealer yet?

I took it to my mechanic and there were no fault codes, it was clean. She thinks it might ber the fuel pump so right now I am driving it as normal and if it happens again I will test the engine fuel pressure with an external fuel pressure gag.

Whats interesting is that it is not a consistent issue correct? It has happened to me 3 times, all occuring between 70 - 101k miles. The first time was after a road trip to Florida. Car was low on gas (bout 1/4 tank). Stalled out while driving, just started hesitating, choking, then died. After letting it rest for aprox. 30 min. she was fine again. The most recent stall was the same situation but after a 18 hour road trip from MN. The car had NO issues for 9 months in the winter while we were in MN, then after an 18 hour road trip of perfect driving, 28 mpg, she stalls out in Atlanta traffic.

So I'm perplexed...our issues could be completely non-related, but what you experienced certainly was the same thing. Vapor lock I would think is not an issue due to the high pressure fuel pumps we have...

Let me know if you experience it again, I'm very curious. As for now...I think I'll have to run some tests before replacing any parts...do you know what your fuel trim measurements are?

I have a 2008 X3 that I purchased pre-owned 2 years ago. Several weeks ago I was driving on the interstate here in NY and just like that I had no power. I got onto the shoulder, turned the ignition to off and when I turned it on, it started right up again. I drove a couple of hundred miles and then on two separate occasions since that incident, the power would just kick out and come back again in an instant. I could feel the power stop and return. It's the type of thing that happens, you do not know why, but your kind of waiting for it to happen and strand you somewhere you don't want to be stranded.
So I just brought the car to my mechanic who is BMW certified and he checked the engine and came up with 9 codes that all lead back to the Valvetronics. You can look it up on line (little too technical for us non-mechanic types) but my car is in the shop pending further investigation. Calling my mechanic today, he said that there is a Valvetronic sensor that could be faulty - but he has to look further.
Once I get my final results (an bill), I will let everyone know what the outcome is.

Whats interesting is that it is not a consistent issue correct? It has happened to me 3 times, all occuring between 70 - 101k miles. The first time was after a road trip to Florida. Car was low on gas (bout 1/4 tank). Stalled out while driving, just started hesitating, choking, then died. After letting it rest for aprox. 30 min. she was fine again. The most recent stall was the same situation but after a 18 hour road trip from MN. The car had NO issues for 9 months in the winter while we were in MN, then after an 18 hour road trip of perfect driving, 28 mpg, she stalls out in Atlanta traffic.

So I'm perplexed...our issues could be completely non-related, but what you experienced certainly was the same thing. Vapor lock I would think is not an issue due to the high pressure fuel pumps we have...

Let me know if you experience it again, I'm very curious. As for now...I think I'll have to run some tests before replacing any parts...do you know what your fuel trim measurements are?

(Unfortunately) this is an interesting topic. I have precisely same inconsistent behavior. In consistent in the sense that i can't reproduce the behavior at will.
Here are my details:
x3 06 ~80K. It's after lease vehicle I own it since 09. Before summer 2012 no issues.
first occurrence - on a hot ( 100F) day after driving for about 40 minutes. After 10 minutes stop car could not hold RPMs stable and basically was dropping rpms unless i had accelerator down. I did notice that there was a delay of a few seconds before me flooring gas pedal and rpms coming up. After 40 minutes car started and there were no codes.
Since then i noticed that when the gas tank is close to 0 ( needle is on the last mark) car tends to vibrate and rpms (while not driving) are going up and down between 800 and 1000.
A month or so ago it lost all power while i was driving. I restarted it and it started to vibrate but i managed to get home al'right.
I have to note that vibration and variance in RPMs don't happened everyday. At this point it looks like they happened @ will or (maybe?) when the gas is very low.
I did blamed on gas quality but i changes a few gas stations and noticed no difference.

............ on a hot ( 100F) day after driving for about 40 minutes. After 10 minutes stop car could not hold RPMs stable and basically was dropping rpms unless i had accelerator down

..... noticed that when the gas tank is close to 0 ( needle is on the last mark) car tends to vibrate and rpms (while not driving)

...... I have to note that vibration and variance in RPMs don't happened everyday. At this point it looks like they happened @ will or (maybe?) when the gas is very low.

Lots of possibilities I suppose.

Don't think vapor lock is a factor with most cars these days.

Could be the first signs of a failing fuel pump (not a common problem with the X3).

Not sure about running with the gas gauge needle close to the stop.
The Owner manual has something to say on that (attached).

Applies to any vehicle, of course, but best to avoid sucking any bottom of the tank sediment up into the fuel filter by gassing up as soon as the light comes on.

Not always possible or convenient, of course.
Or you pull in to fill up and see a tanker truck is in the process of filling up the station's underground tanks.
Best to avoid buying gas when that's happening as their storage tank is getting stirred up.

Used car dealers tend to understandably keep low gas levels in all their cars and just splash in a gallon for test drives.
That can't be too good, and if a car stays on the lot unsold for months with little fuel in the tank some rust may be accumulating.

Replacing the fuel filter in an X3 may not be an easy or inexpensive job, but in some cases might be well worth doing.

Lots of possibilities I suppose.
.. Could be the first signs of a failing fuel pump (not a common problem with the X3).

Not sure about running with the gas gauge needle close to the stop.
The Owner manual has something to say on that (attached).

Applies to any vehicle, of course, but best to avoid sucking any bottom of the tank sediment up into the fuel filter by gassing up as soon as the light comes on.

... Replacing the fuel filter in an X3 may not be an easy or inexpensive job, but in some cases might be well worth doing.

that's what 2 mechanics told me. Todays' reading on the codes gave O2 sensors failing . But i think the problem is with that tube that delivers air to the engine. It's probably cracked and that might cause the sensors going silly.

Is there a way to clean up the gas pump or tank without shelving out a billion dollars? Btw, what, in a ballpark, for this type of work?

One of the big problems with keeping a low level of fuel in a tank is not usually the rust, it is the formation of water from condensation. A good fuel conditioner (Techron is one) will remove this water (actually it causes the water to bond with the fuel and burn off) and solve that problem. A cheap fix.